1. Field
The present application relates generally to network switches and, more specifically, to a packet switching appliance with a packet switching daughter board.
2. Related Art
In a packet-switching network, the transmission, routing, forwarding, and the like of messages between the terminals in the packet-switching network are broken into one or more packets. Typically, data packets transmitted or routed through the packet switching network comprise three elements: a header, a payload, and a trailer. The header may comprise several identifiers such as source and destination terminal addresses, VLAN tag, packet size, packet protocol, and the like. The payload is the core data for delivery, other than header or trailer, which is being transmitted. The trailer typically identifies the end of the packet and may comprise error checking information. Data packets may conform to a number of packet formats such as IEEE 802.1D or 802.1Q.
Associated with each terminal in the packet-switching network is a unique terminal address. Each of the packets of a message has a source terminal address, a destination terminal address, and a payload, which contains at least a portion of the message. The source terminal address is the terminal address of the source terminal of the packet. The destination terminal address is the terminal address of the destination terminal of the packet. Further, each of the packets of a message may take different paths to the destination terminal, depending on the availability of communication channels, and may arrive at different times. The complete message is reassembled from the packets of the message at the destination terminal. One skilled in the art commonly refers to the source terminal address and the destination terminal address as the source address and the destination address, respectively.
Packet switch appliances can be used to forward packets in the packet-switching network, based on their address information, to their destination terminals. Typically, packet switch appliances have one or more network ports for connection to the packet-switching network. The network port of a packet switch appliance can include a filter, which either drops or forwards packets. Packet switch appliances may also have one or more instrument ports connected to one or more network instruments, typically used to monitor packet traffic, such as packet sniffers, intrusion detection systems, intrusion prevention systems, or forensic recorders.
The packet switching demands of networks may vary greatly depending on the size and complexity of the network and the amount of packet traffic. Users may also desire expanded packet handling and processing functionality beyond basic switching, routing, and filtering. Users may also wish to deploy various network instruments for monitoring packet traffic.